[Numpy-discussion] Need help for implementing a fast clip in numpy (was slow clip)

Christopher Barker Chris.Barker at noaa.gov
Wed Jan 10 17:19:07 CST 2007



A. M. Archibald wrote:

> Why not write the algorithm in C? 

I did just that a while back, for Numeric. I've enclosed the code for 
reference.

Unfortunately, I never did figure out an efficient way to write this 
sort of thing for all types, so it only does doubles. Also, it does a 
bunch of special casing for discontiguous vs. contiguous arrays, and 
clipping to an array vs a scaler for the min and max arguments.

Do what you will with  the code...

look for NumericExtras_fastclip in with the rest of the stuff in there 
-- much of which is now obsolete -- I haven't touched this is a few years.


-Chris

NOTE: is there a clean and efficient way to write custom functions of 
this sort for all types and both contiguous and discontiguous arrays? I 
guess I'm imaging some smart iterators and a micro version of C++ 
templates -- or maybe use C++ templates themselves.




-- 
Christopher Barker, Ph.D.
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Chris.Barker at noaa.gov
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